I don’t get it.
No seriously, could somebody explain it to me? And let’s pretend that you’re explaining it to someone who dislikes the very concept of Mario and therefore knows nothing about it whatsoever. Hypothetically.

The alt-text isn’t right though. Despite what the alt-text says, it is, in and of itself, the alt-text. The “ceci n’est pas un …” doesn’t apply with the alt-text, because a text by very nature is something depicted, while an object such as a pipe is not.
And why does the Italian plumber speak French?